The proposal is to test ontogenetic change in how acute ethanol ingestion affects learning, memory and stimulus selection. Recent surveys indicate substantial consumption of ethanol among children, particularly adolescents, but the consequences for learning and memory when developing children or animals are under the influence of ethanol is unknown. With emphasis on periadolescence, in compariosn with earlier and later periods, we will test with an animal model (the rat) the influence of acute ethanol as an agent of contextual control over the expression of memory, the interaction between effects of ethanol and sources of stress, the effects of ethanol on rate of forgetting, and preliminary indications that ethanol may influence what is learned rather than (or as well as) the learning process itself, perhaps especially at ceartain points in ontogency. Through-out, emphasis will be on the careful derivation of functions relating dose of ethanol with learning and memory, assessed in circumstances in which ontogenetic comparisons may be considered. Equivalency doses will be chosen to equate brain alcohol levels (BrAL) across age. The conditioning and test procedures will be rapidly conducted, equally so across agrees to enable containment of the duration of conditioning and testing within the peak BrAL for all animals at all ages. The proposed experiments address the following questions about the influence of ethanol on learning and retention at different ontogenetic periods: (1) When ethanol produes state dependent retention, how does this effect vary with age? (2) How is learning influenced by ethanol in the presence or absence of isolation stress at different ages? (3) What effect does ethanol have on rate of forgetting in animals of different ages? (4) Does ethanol influence the selection of stimuli attended to and/or learned and does this vary with age? (5) Does ethanol affect learning in the absence of reimforcers that are strong biologically significant stimuli in a manner similar to that observed when reinforcers such as footshock or food are employed, and is the relationship between such effects dependent upon ontogenetic status? (6) Does ethanol have effects on periadolescent animals that differ from those at younger or older ages, as has been observed for other drugs that alter central catecholaminergic activity and do these include effects that alter the learning and/or stimulus selection of these periadolescent animals?